What could explain δ13C signatures in biocrust cyanobacteria of drylands?

Eva Stricker; Grace Cain; Jennifer A. Rudgers; Robert L Sinsabaugh; Vanessa Fernandes; Corey Nelson; Ana Giraldo Silva; Ferran Garcia-Pichel; Jayne Belnap; Anthony Darrouzet-Nardi

doi:10.1007/s00248-020-01536-3

USGS · 70216547

What could explain δ13C signatures in biocrust cyanobacteria of drylands?

Eva Stricker·Grace Cain·Jennifer A. Rudgers·Robert L Sinsabaugh·Vanessa Fernandes·Corey Nelson·Ana Giraldo Silva·Ferran Garcia-Pichel·Jayne Belnap·Anthony Darrouzet-Nardi

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Abstract

Dryland ecosystems are increasing in geographic extent and contribute greatly to interannual variability in global carbon dynamics. Disentangling interactions among dominant primary producers, including plants and autotrophic microbes, can help partition their contributions to dryland C dynamics. We measured the δ 13 C signatures of biological soil crust cyanobacteria and dominant plant species (C 3 and C 4 ) across a regional scale in the southwestern USA to determine if biocrust cyanobacteria were coupled to plant productivity (using plant-derived C mixotrophically), or independent of plant activity (and therefore purely autotrophic). Cyanobacterial assemblages located next to all C 3 plants and one C 4 species had consistently more negative δ 13 C (by 2‰) than the cyanobacteria collected from plant interspaces or adjacent to two C 4 Bouteloua grass species. The differences among cyanobacterial assemblages in δ 13 C could not be explained by cyanobacterial community composition, photosynthetic capacity, or any measured leaf or root characteristics (all slopes not different from zero). Thus, microsite differences in abiotic conditions near plants, rather than biotic interactions, remain a likely mechanism underlying the observed δ 13 C patterns to be tested experimentally.

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Microbial Ecology Article

Source-reported bounding extent: 32.36372329228304° to 33.71291698851023° latitude; -107.81982421874999° to -106.5289306640625° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

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Eva Stricker, Grace Cain, Jennifer A. Rudgers, Robert L Sinsabaugh, Vanessa Fernandes, Corey Nelson, Ana Giraldo Silva, Ferran Garcia-Pichel, Jayne Belnap, Anthony Darrouzet-Nardi. 2020-07-03. What could explain δ13C signatures in biocrust cyanobacteria of drylands?. https://doi.org/10.1007/s00248-020-01536-3

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